<let/x=0/>
<let/show=true/>
<if=show>
  <lifecycle
    onMount() { document.getElementById("ref").textContent = "Mount " + x; }
    onUpdate() { document.getElementById("ref").textContent = "Update " + x; }
    onDestroy() { document.getElementById("ref").textContent = "Destroy"; }
  />
</if>
<div#ref/>
<button#increment on-click() { x++ }>Increment</button>
<button#toggle on-click() { show = !show }>Toggle</button>
